https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65824
--- Comment #2 from vries at gcc dot gnu.org ---
minimal version of stdarg-1.c, returns 14 if correct, but 12 for current
failure, indicating that the the first and resultless va_arg has been ignored:
...
include <stdarg.h>
extern void exit (int);
int
f6 (int i, ...)
{
int res;
va_list ap;
va_start (ap, i);
va_arg (ap, long);
res = va_arg (ap, long);
va_end (ap);
return res;
}
int
main (void)
{
int res = f6 (7, 12L, 14L);
exit (res);
}
...
The expression returned by gimpify_va_arg_internal is:
...
(gdb) call debug_generic_expr ($1)
*D.2689 >= 0 ? ap.__stack = (void *) ((long int) D.2690 + 15 & -8);, (long int
*) D.2690; : ap.__gr_offs = D.2689 + 8;, ap.__gr_offs > 0 ? ap.__stack = (void
*) ((long int) D.2690 + 15 & -8);, (long int *) D.2690; : (long int *)
ap.__gr_top + (sizetype) D.2689;
...
Indeed, not side-effect free.
This is most likely a duplicate of PR65818.
